Application of real-time shear wave elastography on the diagnosis of thyroid nodules in pilots

Objective To explore the effects of real-time shear wave elastography (SWE) on diagnosing benign and malignant thyroid nodules in pilots. Methods Fifty-two pilots were diagnosed as thyroid nodules (60 nodules) in 456th Hospital of People′s Liberation Army from May 2014 to May 2017. They were checked by real-time shear wave elastography and the Young's moduli of nodules and normal thyroid tissues were recorded. The Young's modulus of patients′ normal thyroid tissues was taken as control value and was compared to that of thyroid nodules. By referring to the pathological examination result as the gold stand, the receiver operating characteristic (ROC) curve was plotted to determine if the thyroid nodules were benign or malignant in SWE diagnosis. The area under the ROC curve (AUC) was compared to determine the best diagnostic boundary. Results Out of 52 cases of thyroid nodules, 43 cases (48 nodules) were benign lesions. The pathological types included nodular goiter (n=33) and adenomas (n=15). There were 9 cases of malignant lesions (12 nodules) including papillary carcinoma (n=10) and small papillary carcinoma (n=2). The maximum, average and minimum Young′s modulus values showed significant difference between control group and those with thyroid adenoma, nodular goiter and thyroid malignant tumor (F=258.19, 268.39, 421.84, P<0.01). The mean, maximum and minimum Young′s modulus values of malignant nodules were (58.68±9.27) kPa, (78.64±11.53) kPa and (38.51±5.81) kPa respectively, and were higher than those of benign thyroid nodules (41.48±5.69) kPa, (52.23±7.71) kPa, (31.51±2.47) kPa. The differences had statistical significance (t=8.16, 9.55, 6.44, P<0.01). The AUC corresponding to the maximum, average and minimum Young′s modulus value was 0.929, 0.863 and 0.798 respectively. The best diagnostic efficiency was at the maximum Young′s modulus in the nodule and its diagnostic threshold was 54.42 kPa. Conclusions The Young′s modulus of benign thyroid nodules is smaller than that of malignant nodules in pilots. Applying the maximum value of the Young′s modulus enables better diagnosis accuracy than using its average or minimum value in determining malignant thyroid nodules. The quantitative SWE is helpful for diagnosing benign and malignant thyroid nodules in pilots. Key words: Thyroid nodule; Ultrasonography; Shear wave elastography; Pilots